The sole of a human foot is formed with a transverse arch, a medial longitudinal arch, and a lateral longitudinal arch. If the skeleton of the foot constituting these arches loses its shape, body parts such as the foot, a knee, a waist, a back, a shoulder, and the like get distorted, or become painful, which may lead to a failure in the body. This is well known. The use of a shoe insole appropriate for the foot of a user in a shoe is helpful in preventing such problems.
For example, Patent Literatures 1 and 2 disclose a shoe insole having an arch support function. Patent Literature 1 discloses that a shoe insole is manufactured in such a manner that first to three pads are attached onto an insole body plate to correspond to three arches, respectively, and a cover sheet is applied to the insole body plate attached with the three pads, from an upper side.
Patent Literature 2 describes that since the size, shape and the like of the human foot are varied from person to person, it is difficult to select or manufacture the first to third pads with sizes and shapes which are appropriate for the user of the shoe insole and to place these pads in correct positions, in the configuration of Patent Literature 1.
Patent Literature 2 discloses a manufacturing method of a shoe insole including an upper plate and a lower plate which constitute a sole (foot bottom) plate and are placed to be vertically adjacent to each other, in which a mixture of a base compound and a curing agent of two-pack liquid silicon rubber is placed on the upper surface of the lower plate in positions which substantially correspond to the arches of the sole of the foot, respectively, the user pushes the upper plate with a pressure with the sole of the foot, from an upper side, in a state in which the upper plate overlaps with the lower plate, and thus the silicon rubber is molded and cured to conform to the shapes of the arches.